基于电火花加工方法的铍铜合金表面微结构制备及其浸润性研究

Beryllium copper alloys are widely used in liquid floated gyroscope and related fields owing to their excellent properties. In this proposal, we take the fabrication of the ball sockets with high precision as an entry point, which is a miniature ball-disc-rotor liquid floated gyroscope. The electrical discharge machining (EDM) technology is used to machine beryllium copper alloys to realize precise fabrication of the part structures and surface characteristics. Further, the effects of EDMed surface morphology on the wettability and drag reduction are analyzed. At last, the basic theory, technic and the control strategy during the processing are studied systematically. The simulation model of beryllium copper alloys in EDM with multi-physics field is established, which is used to reveal the basic technological rule. The evaluation method and compensation strategy of electrode wear during different types of EDM are studied, so as to fabricate three-dimensional structure with high accuracy. The evaluation method of surface morphology is proposed based on the wavelet analysis and fractal theory. The relationship between surface morphology and wettability is established based on the material removal mechanisms of EDM and surface morphology required for wettability. Regulating method for surface wettability based on EDMed surface is proposed, and the effects of surface wettability on the fluid drag reduction are studied. This study can broaden the application fields of EMD effectively, meanwhile it will provide new ideas for the engineering fabrication of surface with wettability.

铍铜合金以其优异的性能而在液浮陀螺及相关领域得到广泛应用。本项目以某微型球碟转子式液浮陀螺转子偶件铍铜球窝的高精度加工为切入点，研究铍铜合金材料的电火花加工方法，实现其结构及表面特征的精确调控；研究和分析电火花加工表面形貌特征及其对零件浸润性和减阻特性的影响规律；深入探讨上述过程中相关的基础理论、工艺和控制策略等。建立铍铜合金材料电火花加工的多物理场仿真模型，揭示其基本工艺规律；研究不同电火花加工方式下电极损耗的评定方法及补偿策略，实现三维结构的精密电火花加工；基于小波分析和分形理论，提出电火花加工表面形貌的评定方法；充分利用电火花加工材料去除机制和浸润性表面所需的表面形貌特点，建立电火花加工表面形貌与浸润性之间的关系；提出基于电火花加工的表面浸润性调控方法，并探索表面浸润性对流体减阻性能的影响规律。本项研究不仅可拓宽电火花加工的应用范围，同时也将为工程化制备浸润性表面提供新思路。

本项目以液浮陀螺转子偶件铍铜合金微球窝的高精度加工为研究背景，对铍铜合金等材料的微细电火花工艺特性和表面理化性能进行深入研究。通过原理探索和工艺改进，实现了高精度高表面质量的微细电火花加工；以电火花加工后的表面形成过程为切入点，结合单脉冲放电凹坑的形成过程分析，对表面形貌进行理论评定，提取特征参数并建立表面特征与工艺参数之间的联系，重构表面的曲面方程。利用获得的拟合曲面；采用吉布斯自由能原理和水滴力平衡分析，实现了接触角的理论计算，能够对选定工艺参数下表面润湿性进行预测，为超疏水表面制备工艺探索提供理论依据；结合电火花加工的表面评定和润湿性探究，通过流场仿真分析和实验测试，对电火花加工表面的减阻特性进行了深入研究，证明了低表面能辅助下表面的流体减阻能力；基于电火花加工形成的表面粗糙结构，进行电火花电化学组合法超疏水表面制备技术研究，构建的分层微纳米复合结构对于提升表面稳定性和耐磨性发挥重要价值；表征和实验测试证明了工艺方案制得超疏水表面的优异性能；针对微球窝结构进行微细电火花工艺探索，结合碳沉积法实现了超疏水球窝的制备。本项目为微细电火花在微系统和微流控技术领域应用提供了理论依据和工艺新思路。